Grandma sent Johnny some money for his birthday.
Johnny spent all of it in five stores.
In each store, he spent Rs 1.00 more than half of what he had when he came in.
How much money did he get from grandma?

Work backwards, is the easiest way to get the answer.
If he has no money left over, then at the last store, he came in with Rs 2. Half of 2 is 1, and he paid one Rupee more than that, Rs 2.
Reiterating:
2 + 1 = 3 * 2 = 6
6 + 1 = 7 * 2 = 14
14 + 1 = 15 * 2 = 30
30 + 1 = 31 * 2 = 62.Hence answer is 62